/**
 * 构造树型结构数据
 * @param {*} data 数据源
 * @param {*} id id字段 默认 'id'
 * @param {*} parentId 父节点字段 默认 'parentId'
 * @param {*} children 孩子节点字段 默认 'children'
 */
// 递归
function toTreeData(data, id, parentId, children) {
	let config = {
	    id: id || 'id',
	    parentId: parentId || 'parentId',
	    childrenList: children || 'children'
	  };
	
	  var childrenListMap = {};
	  var nodeIds = {};
	  var tree = [];
	
	  for (let d of data) {
	    let parentId = d[config.parentId];
	    if (childrenListMap[parentId] == null) {
	      childrenListMap[parentId] = [];
	    }
	    nodeIds[d[config.id]] = d;
	    childrenListMap[parentId].push(d);
	  }
	
	  for (let d of data) {
	    let parentId = d[config.parentId];
	    if (nodeIds[parentId] == null) {
	      tree.push(d);
	    }
	  }
	
	  for (let t of tree) {
	    adaptToChildrenList(t);
	  }
	
	  function adaptToChildrenList(o) {
	    if (childrenListMap[o[config.id]] !== null) {
	      o[config.childrenList] = childrenListMap[o[config.id]];
	    }
	    if (o[config.childrenList]) {
	      for (let c of o[config.childrenList]) {
	        adaptToChildrenList(c);
	      }
	    }
	  }
	return tree;
}


// 记得导出定义的方法
export {
	toTreeData
}


